This invention relates to a substrate treatment apparatus for applying a liquid resist or a developer to a substrate such as a semiconductor wafer.
Photolithography is used in a process for manufacturing semiconductor devices. In this technique, a resist is coated onto a semiconductor wafer, and the coated resist is subjected to an exposure treatment so as to have a predetermined pattern, and then to a developing treatment. As a result, a resist film of a predetermined pattern is formed. Thereafter, further film forming and etching are performed to form a circuit of a predetermined pattern. A series of resist treatments as above is performed using, for example, a coating/developing treatment system as described in U.S. Pat. No. 5,664,254. This conventional system has two resist coating units to enhance the throughput. More specifically, in this system, two unit chambers 101 and 102 are provided at the same level and adjacent to each other, and a main arm mechanism 22 is provided on an extended line of the boundary between the chambers, as is shown in FIG. 1. The main arm mechanism 22 comprises a Z-axis driving mechanism for vertically moving an arm holder 48, a rotary mechanism for moving the arm holder 48 through an angle .theta. about the Z-axis, and an advancing/retreating mechanism for advancing and retreating the arm holder 48. A spin chuck 105 is provided at a substantially center portion of each of the unit chambers 101 and 102. Further, a resist coating unit 106 and a side rinse unit 107 are provided at opposite side portions of each of the chambers 101 and 102.
For example, to carry a wafer W into the unit chamber 101 by the main arm mechanism 22, the arm holder 48 is raised to the same level as the chamber 101, then swung about the Z-axis, and extended and inserted into the chamber 101 through a chamber inlet 103 to thereby place the wafer W on the spin chuck 105 therein. On the other hand, to carry the wafer W into the other unit chamber 102 by the main arm mechanism 22, the arm holder 48 is raised to the same level as the chamber 102, then swung about the Z-axis, and extended and inserted into the chamber 102 through a chamber inlet 104 to thereby place the wafer W on the spin chuck 105 therein.
Since, however, the resist coating unit 106 and the side rinse unit 107 have different sizes, the arm holder 48 must be swung through different angles .theta. 1 and .theta. 2 and extended over different distances between the case where it transfers the wafer W into the first chamber 101 and the case where it transfers it into the second chamber 102. To this end, the main arm mechanism 22 and software for controlling the operation of the mechanism 22 must be made complicated, which results in a high cost.